The invention relates to a method for operating a building closure, preferably having the shape of an overhead sectional door or of a garage door including a spring-loaded counterweight device and an electrical drive device, which is charged by a control apparatus.
Such a door is revealed for example in the document DE 10 2006 1011 305 B4 as well as in U.S. Pat. No. 5,016,391.
Generally, building closure of the aforementioned species require a counterweight force which allows for moving the door leaf, either manually or by means of an electrical drive device, more easily between the open position and the closed position without any problems. Overhead door systems very often depend on one or more torsion springs to provide said counterweight force.
As the forces, developed by the torsion spring, vary depending on the execution of the door and as a result of tolerances, it is difficult to precisely maintain the open position of a door. A maximum open position of the door is desired in order to have the entire passage opening available. However, in this open position, the torsion spring counteracts the strongest the force developed by the drive unit, which may result in failure to achieve a maximum opening width.
Another arising problem is that, when in the closed position, such a building closure should absolutely not be manually pushed open without authorization. Currently utilized motors usually have a gear, which includes a self-locking device. However, this self-locking device can be overcome when applying sufficient force. Separate push-open security devices and additional locks are often too expensive.
Therefore, it is the object of the invention, on the one hand to find a solution for the shortfalls of the state-of-the-art in the open position, respectively to likewise provide a solution when the door is in the closed position. In this case, expensive solutions, such as equipping the motor with an auxiliary winding and energizing the latter in the terminal positions should be foregone. Furthermore, mechanical interlocking units are not desired either, because they would increase the cost for such a building closure.